1. Field of the Invention
The present invention relates to a method of switching a communication mode to voice communication in response to a voice communication request during data communication in a mobile station and a system for managing a service using the same and, more particularly, to a technology capable of simultaneously providing both voice and data services by making voice communication when data communication is operating.
2. Description of the Related Art
FIG. 1 is a schematic diagram showing a typical mobile communication system.
A mobile station (MS) 110 is a portable device which acts as a normal telephone whilst being able to move over a wide area. The MS 110 does not only support voice calls; it can also send and receive data and faxes, send short messages, access wireless application protocol (WAP) services, and provide full Internet access.
A base station (BS) 120 is a low-power multi-channel two-way radio station which is in a fixed location and is typically used by the MS 110.
A mobile switching center (MSC) 130 serving as a network node in a wireless telecommunications network is effectively a sophisticated telephone exchange which provides circuit switched services to mobile stations in a certain geographical area. Tasks of the MSC 130 include delivering calls to subscribers as they arrive based on information from a visitors location register (VLR), connecting outgoing calls to other mobile subscribers, and carrying out handovers from one MSC to another without interrupting the call.
A mobile carrier (MC) 140 provides mobile communications services via SS7 (Signaling System 7), a set of protocols defined by ITU-T (Telecommunication Standardization Sector of the International Telecommunications Union) used to set up telephone calls. For establishing a mobile communications network, the MC 140 is coupled to a variety of systems as follows: a home location register (HLR), a short message service center (SMSC), a voice mail system (VMS), a billing system, etc. The primary functions of the HLR are to send subscriber data to a VLR where a subscriber has just arrived, to pass on the roaming number requested from the subscriber's VLR to the Gateway MSC or SMSC in order to allow incoming SMSs or text messages, and to remove subscriber data from the old VLR where a subscriber has moved from. The SMSC supports the sending of text messages displayed on a liquid crystal display (LCD) provided in the MS. The VMS allows subscribers to receive a voice message through a speaker provided in the MS. The billing system performs the process of sending accounts to subscribers for voice and data communications services.
An Interworking Function (IWF) 150 is used to enable data communications between an SS7-based mobile communication network and a Transmission Control Protocol/Internet Protocol (TCP/IP)-based Internet network. During data communications, the IWF 150 exchanges subscriber information, accounts, etc. with the MSC, the HLR, the billing system, etc.
A gateway (G/W) 160 is a network node equipped for interfacing with another network that uses different protocols. The G/W 160 connects the SS7-based mobile communication network with the TCP/IP-based Internet network by performing the required protocol conversions.
A Content Management System (CMS) 170, a system used to organize and facilitate collaborative content creation, manages the content of web sites to be transmitted to the MS. The CMS 170 is also responsible for registering the authority of content providers (CPs), and managing the CPs.
Under the control of the CMS 170, a Domain Name System (DNS) 180 provides an IP address associated with a domain name of each site providing content in response to a content transmission request from the MS.
At least one CP 190 connected to the CMS 170 transmits to the MS multimedia contents such as graphic images, animations, and melodies in response to a request from the MS.
Operation of providing a voice communication service in a typical mobile communication system with the above-mentioned configurations is now set forth.
Once the MS 110 is powered on, a call origination signal is transmitted to the BS 120 over an access channel. The BS 120 establishes a traffic channel to transmit a channel assignment signal to the MS 110 over a paging channel. The MS 110 confirms the traffic channel establishment and transmits a traffic channel preamble to the BS 120. The BS 120 acquires a reverse traffic channel and then transmits an acknowledge signal to the MS 110 for call setup.
During the call setup phase, the MSC 130 transmits a communication request signal to a called party's mobile station MS2 through the BS 120 in response to a communication request from a calling party's mobile station MS1, and requests a response thereto from the MS2. Upon receiving the response from the MS2, the MSC 130 connects the MS1 with the MS2 for voice communication therebetween, and controls voice data frame transmission between the MS1 and the MS2 over a traffic channel.
On the other hand, operation of providing a data communication service in a typical mobile communication system with the above-mentioned configurations is now set forth.
Once a mobile communication subscriber accesses a data communication service through the MS 110, the IWF 150 requests initial access from the DNS 180. The DNS 180 transmits to the CMS 170 a mobile IP address assigned to the MS 110 and requests main menu access from the MS 110. The CMS 170 provides a main menu to the mobile IP address assigned to the MS 110. When the mobile communication subscriber selects any item in the main menu using the MS 110, the CMS 170 requests the uniform resource locator (URL) of the selected item from the DNS 180. The DNS 180 notifies the CMS 170 of the URL associated with the selected item. The CMS 170 provides a content specified by the URL to the MS 110. The mobile communication subscriber views the content through the MS 110 and requests the CMS 170 to download it to his or her mobile station. When the CMS 170 requests the URL associated with the content from the DNS 180, the DNS 180 notifies the CMS 170 of the URL associated with the content. The CMS 170 pushes the content specified by the URL to the MS110, which in turn loads the content. After the MS 110 requests the CMS 170 to move back to a higher menu level after the downloading operation, the above-mentioned process may be reiterated. Alternatively, upon receiving a request to terminate the process from the MS 110, the CMS 170 requests accounts for the communication services from the billing system.
However, there has been a problem in that the conventional mobile station cannot simultaneously provide the voice and data communications services.
That is, when a calling party makes a telephone call to a called party in data communication, the called party's mobile station MS2 cannot receive the telephone call since it is using a communication channel. At this time, a signal indicating that the MS2 is in use is transmitted to the calling party's mobile station MS1.
If the called party's mobile station MS2 is using a data communication service in the case of the calling party's voice communication request, the MSC 130 informs the calling party's mobile station MS1 of the fact that the MS2 is in use. In this case, the called party can be informed of the fact, through a message mailbox, that the voice communication request was made by the calling party.
The data communication service is typically used for a long time compared to the voice communication. The calling party will attempt to make several calls to the called party since the calling party cannot recognize whether the called party is in voice communication or data communication. Furthermore, the called party cannot be informed of the fact that someone is calling to his or her own mobile station since the called party cannot make voice communication during data communication.
On the other hand, even though a value-added service is available such as a call keeper, which is a function of notifying a called party of the fact that someone has called him or her in case the called party is busy or does not answer, the called party can be informed of the fact only after the data communication in use is terminated.